JP2947921B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an epoxy resin composition used as a semiconductor encapsulating material.

[Conventional technology]

Epoxy resin compositions containing polyfunctional epoxy compounds, phenol novolak-based curing agents, curing accelerators, and inorganic fillers as main components have been recognized to have excellent performance, and in recent years semiconductor encapsulants, which have been growing remarkably, Widely used as.

However, with the increasing integration and size of semiconductors and changes in the method of mounting semiconductors on substrates, performances such as low stress resistance and solder crack resistance are strongly demanded, but conventional resin compositions are difficult to cope with. This is one of the causes of defects such as solder cracks and cracks caused by thermal shock in semiconductors and devices using them.

As a method for solving this problem, it has been proposed to add a block copolymer comprising an alkenyl group-containing aromatic polymer and an organopolysiloxane to a curable epoxy resin (JP-A-58-21417). However, in this block copolymer, it is difficult to control the domain size in the sea-island structure in which polysiloxane is micro-dispersed in the epoxy cured product, so that the heat shock resistance and the solder crack resistance in the heat cycle test are insufficient. In addition, there has been a strong demand for an improvement in moldability typified by an increase in burrs, poor printability, and the like.

In order to solve these problems, a combination of an organopolysiloxane and a copolymer of an aromatic hydrocarbon and an organopolysiloxane (JP-A-61-271319) has been proposed. Poor moldability due to exudation of the organopolysiloxane later, poor storage at high temperature, etc. occur.

It has also been proposed to blend a copolymer of a combination of a short-chain organopolysiloxane and a long-chain organopolysiloxane with an alkenyl group-containing epoxy resin (JP-A-63-238123). In this case, too, it was found that poor moldability was caused by exudation of low molecular weight components based on the short chain length organopolysiloxane.

[Problems to be solved by the invention]

The present invention solves the above-mentioned drawbacks, and provides an epoxy resin composition for semiconductor encapsulation which is excellent in thermal shock resistance and solder crack resistance, does not deteriorate mechanical properties, and is excellent in moldability and high-temperature storage property. It is in.

[Means for solving the problem]

The present invention provides (1) (A) a Si—H group-containing organopolysiloxane-modified polyfunctional epoxy resin represented by the following formula (I): (However, in the formula, R ₁ is a polyfunctional epoxy resin, and R ₂ has 1 to 1 carbon atoms.
3, alkyl and phenyl groups, l, m and n
Wherein (l + m + n) is from 15 to 200, m satisfies 0 to 20, and n satisfies 2 to 50) at least one of the vinyl group-containing organopolysiloxanes represented by the following formula (II): Siloxane (Where R ₃ is an alkyl group having 1 to 3 carbon atoms or a phenyl group, and p and q are those wherein (p + q) is 0 to 50 and q satisfies 0 to 5). (B) a polyfunctional epoxy compound, (C) a phenol novolak-based curing agent, (D) a curing accelerator, and (E) an inorganic filler. A composition.

In the Si—H group-containing organopolysiloxane-modified polyfunctional epoxy resin represented by the formula (I) constituting the present invention, examples of the polyfunctional epoxy resin of R ₁ include a cresol novolak epoxy resin and a phenol novolak epoxy resin. , Alicyclic epoxy resin, bisphenol A novolak epoxy resin, bisphenol A bromide
Various types of polyfunctional epoxy resins, such as a novolak epoxy resin, may be mentioned. However, the structure is not necessarily limited to only one kind of structure, and a mixture of two or more kinds may be used. Among these polyfunctional epoxy resins, an epoxy equivalent of 150 to 250, a softening point of 60 to 130 ° C. and N
It is preferable to remove ionic impurities such as a ⁺ and Cl ⁻ as much as possible. R ₂ includes a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a phenyl group and the like, and is not limited to one kind of structure, but a methyl group is preferable for reducing stress. l, m and n are (l + m + n)
Is 15 to 200, preferably 30 to 100, m is 0 to 20, preferably 0 to 10, and n is 2 to 50, preferably 4 to 30. If the amount exceeds these ranges, the glass transition point is reduced or burrs are increased due to the miniaturization of the sea-island structure in which polysiloxane is micro-dispersed in the epoxy cured product, or the interface between the formed domain and the matrix is bonded. In addition, various problems such as a decrease in bending strength, a decrease in Barcol hardness, a decrease in printability, and a problem in synthesis due to the phase separation accompanying the weakening of the steel cause the object of the present invention to not be achieved. Further, the compound represented by the formula (I) added to the organopolysiloxane-modified polyfunctional epoxy resin having the Si—H group
In the vinyl group-containing organopolysiloxane represented by I), R ₃ may be a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a phenyl group, etc., and is not limited to a single structure, but has a low stress. For this purpose, a methyl group is preferred. p and q are (p + q) from 0 to 50,
Preferably it is 0-10, and p needs to be 0-5. Exceeding these ranges may cause exudation of the silicone component during molding and failure during storage at high temperatures.
This vinyl group-containing organopolysiloxane is subjected to the above-mentioned Si-
It can be introduced into an H-containing organopolysiloxane-modified polyfunctional epoxy resin.

Next, as the polyfunctional epoxy resin (B) constituting the present invention, for example, a cresol novolak epoxy resin,
Containing phenol novolak epoxy resin, alicyclic epoxy resin, bisphenol A novolak epoxy resin, bromide bisphenol A novolak epoxy resin,
And various types of polyfunctional epoxy resins.
The use is not necessarily limited to the use of only one kind, and two or more kinds may be used in combination. Among these polyfunctional epoxy resins, Na ⁺ , Cl ⁻ at an epoxy equivalent of 150 to 250 and a softening point of 60 to 130 ° C.
It is preferable to remove as much as possible ionic impurities. Next, as the phenol novolak-based curing agent (C) constituting the present invention, for example, phenol novolak,
Cresol novolak, xylenol novolak, bisphenol A novolak, resorcinol novolak resin and the like can be mentioned, but the use thereof is not necessarily limited to the use of only one kind, and two or more kinds may be used in combination. Is also good. Among these phenol novolak-based curing agents, the OH equivalent is 80 to 150, and the softening point is 6.
It is preferable to remove ionic impurities such as Na ⁺ and Cl ⁻ at 0 to 120 ° C. as much as possible.

Further, a curing accelerator (D) for the purpose of accelerating the reaction between the polyfunctional epoxy resin and the phenol novolak resin.
Examples thereof include imidazole or a derivative thereof, a tertiary amine derivative, a phosphine derivative, and a cycloamidine derivative.

Examples of the inorganic filler (E) include crystalline silica, fused silica, alumina, calcium carbonate, talc, mica, glass fiber, and the like. These may be used alone or as a mixture of two or more.

Further, the composition ratio of the above composition is such that the organopolysiloxane component contained in the organopolysiloxane-modified polyfunctional epoxy resin (A) is 5 to 50% by weight, preferably 10 to 35% by weight, and 0.3-5.5 in all compositions
% By weight, and preferably from 1.0 to 3.5% by weight. The ratio of the number of moles of the total epoxy groups of the organopolysiloxane-modified epoxy resin (A) and the polyfunctional epoxy compound (B) to the number of moles of the phenolic hydroxyl groups of the phenol novolak curing agent (C) is 0.6 to 1.4.
Is essential, and is preferably 0.9 to 1.0. The content of the curing accelerator (D) in the composition is from 0.08 to 0.
It is 35% by weight, preferably 0.1-0.3% by weight. And
The content of the inorganic filler (E) in the composition is 65 to 90% by weight, preferably 72 to 85% by weight.

In the composition of the present invention, other additives as required, for example, release agents such as natural waxes and synthetic waxes, flame retardants such as hexabromobenzene, decabromobiphenyl ether, antimony trioxide, Colorants such as carbon black and red iron oxide, silane coupling agents, other synthetic rubbers, silicone compounds, thermoplastic resins and the like may be appropriately compounded. After sufficiently mixing the above-mentioned compound with a mixer or the like, the mixture is further melted and mixed by heating with a kneader or a roll, and then cooled and solidified, and then pulverized to obtain the epoxy resin composition for semiconductor encapsulation of the present invention.

[Action]

In the present invention, by adding a vinyl group-containing organopolysiloxane to a Si-H group-containing organopolysiloxane-modified epoxy resin, the branch points introduced into the linear siloxane structure improve the dispersibility, and further improve the curing process. In the agglomerated silicone domain, a quasi-crosslinked structure is provided inside the domain at the branch point in the introduced siloxane structure to prevent the silicone component from exuding to the molded product surface and preventing defects during high-temperature storage. The effect is exhibited.

〔Example〕

(Reference Example (1)) First, a production example of an organopolysiloxane-modified polyfunctional epoxy resin constituting the present invention will be described.

In a 1-liter four-necked flask, an Si-H having an organosiloxane component content of 16.7% by weight represented by the following formula (A) was added.
After 120 g of organopolysiloxane-modified epoxy resin containing a group (abbreviated as Si-Ep) and 440 g of toluene were added, a reflux condenser and a dropping funnel were attached, and azeotropic dehydration was performed for 1 hour. To Then 0.5 g of a 1% solution of chloroplatinic acid in isopropanol was added.
The vinyl group-containing organopolysiloxane (abbreviated as DVS) represented by the following formula (a) in the amount shown in the table is dropped and allowed to react for 3 hours. Then, the solvent was distilled off under reduced pressure to obtain an organopolysiloxane-modified polyfunctional epoxy resin.

(Reference Examples (2) to (6)) Si-Ep was replaced by the following formulas (B) to (D), and the vinyl group-containing organopolysiloxane was replaced with the following formulas (b) to (c) in the amounts shown in Table 1. ) And the same operation as in Reference Example (1) was performed to obtain an organopolysiloxane-modified polyfunctional epoxy resin.

(Note) In the formula, R is an orthocresol novolak epoxy resin (epoxy equivalent: 200, softening point: 62 ° C.).

Examples [1-4] 70 parts by weight of an organopolysiloxane-modified polyfunctional epoxy resin synthesized based on Reference Examples (1) to (4) and a cresol novolak epoxy resin (epoxy equivalent 200, softening point 62) as a polyfunctional epoxy compound C) 30 parts by weight, 40 parts by weight of a phenol novolak resin (OH equivalent: 105, softening point 100 ° C.) as a phenol novolak-based curing agent, 4 parts by weight of triphenylphosphine as a curing accelerator, 530 parts by weight of fused silica as an inorganic filler, Brominated phenol novolak epoxy resin (bromine content 30% by weight,
Epoxy equivalent 280, softening point 71 ° C) 10 parts by weight, 20 parts by weight of antimony trioxide, 3 parts by weight of a silane coupling agent, 5 parts by weight of carnauba wax, 5 parts by weight of carbon black are sufficiently mixed at room temperature. Knead at 100 ° C,
After cooling, the mixture was pulverized into tablets to produce four types of the epoxy resin compositions for semiconductor encapsulation of the present invention.

Comparative Examples [1-2] Two types of epoxy resin compositions were produced using the organopolysiloxane-modified epoxy resin synthesized based on Reference Examples (5) and (6) in the same manner as in the Examples.

The stain resistance, resin burr, etc. of the epoxy resin compositions produced as these Examples and Comparative Examples were determined using a transfer molding machine (molding conditions: mold temperature: 175 ° C., curing time: 2 minutes) and obtained. The molded product was cured at 175 ° C. for 4 hours, and the sealability, thermal shock resistance, solder resistance, mechanical strength, and the like of the package were evaluated by various tests (A) to (K). Table 2 shows the evaluation results.

(A) Spiral flow value A spiral flow value was measured at a molding temperature of 175 ° C. and a molding pressure of 70 kg / cm ² using a mold conforming to the EMMI standard.

(A) Burr After molding, the length of the resin burr at the vent portion was measured.

(C) Barcol hardness Molding was performed at a molding temperature of 175 ° C., a molding pressure of 70 kg / cm ² , and a molding time of 2 minutes.

(D) Moldability The number of molding shots before the occurrence of mold fogging was evaluated as ○ when the number was 2000 or more, × when the number was 1000 or less, and Δ when the number was 1000 to 2000.

(E) Stamping property The molded article of the 10th shot was used, and it was evaluated whether or not the stamping was peeled off with a cellophane tape after stamping. Those that did not peel off were represented by 、, those that peeled off were represented by x, and the middle was represented by Δ.

(F) Mechanical strength (flexural modulus, flexural strength) Molding temperature 175 ° C, molding pressure 70Kg / cm according to JIS-K6911
^2. Measurement was performed on a molded article having a molding time of 2 minutes and post-curing at 175 ° C. for 4 hours.

(G) Glass transition point The value when the temperature was increased at a rate of 5 ° C. per minute by a dilatometer was measured.

(H) Thermal shock resistance Molding temperature: 175 ° C, molding pressure: 70 kg / cm ² , molding time: 2 minutes, post-curing at 175 ° C, 8 hours, -65 ° C x 15 minutes, 1
A heat cycle of 50 ° C. × 15 minutes was repeated, and the rate of occurrence of resin cracks after 1000 cycles was measured.

(G) Solder resistance Molding temperature: 175 ° C, molding pressure: 70 kg / cm ² , molding time: 2 minutes, post-curing at 175 ° C, 8 hours, and after treatment at 85 ° C, 85% steam for 144 hours. The resin was immersed in a 260 ° C. solder bath for 10 seconds, and the rate of occurrence of resin cracks was measured.

(G) High-temperature storage characteristics The weight loss rate (%) of a 100 mm × 10 mm × 4 mm test piece when stored at 200 ° C. for 1000 hours was measured.

〔The invention's effect〕

The present invention relates to an organopolysiloxane-modified polyfunctional epoxy resin obtained by adding an alkenyl group-containing epoxy compound and an alkenyl group-containing phenol compound to an organopolysiloxane-modified polyfunctional epoxy resin having a Si-H group. An epoxy resin composition for semiconductor encapsulation that has the effects of thermal shock resistance and solder cracking resistance, and is excellent in moldability and high-temperature storage properties by being blended with a system curing agent, curing accelerator, and inorganic filler. Was.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ identification code FI H01L 23/31 (58) Investigated field (Int.Cl. ⁶ , DB name) C08G 59/20-59/38 C08G 59/62 C08L 63/00-63/10 H01L 23/29

Claims (1)

(57) [Claims] (A) An organopolysiloxane-modified polyfunctional epoxy resin containing a Si—H group represented by the following formula (I): (However, in the formula, R ₁ is a polyfunctional epoxy resin, and R ₂ has 1 to 1 carbon atoms.
3, alkyl and phenyl groups, l, m and n
Wherein (l + m + n) is from 15 to 200, m satisfies 0 to 20, and n satisfies 2 to 50) at least one of the vinyl group-containing organopolysiloxanes represented by the following formula (II): Siloxane (Where R ₃ is an alkyl group having 1 to 3 carbon atoms or a phenyl group, and p and q are those wherein (p + q) is 0 to 50 and q satisfies 0 to 5). (B) a polyfunctional epoxy compound, (C) a phenol novolak-based curing agent, (D) a curing accelerator, and (E) an inorganic filler. Composition.